Hollow spaces in an object under investigation, for example vascular pathologies, in particular intracranial vascular pathologies, are frequently dealt with by means of a catheter introduced into the femoral artery and fed via the blood vessels to the site of the lesion. As a rule the positioning and/or location of the catheter is performed using continuously pulsed X-ray transillumination to capture two dimensional projection data sets, together with the application of contrast medium. In so doing it often proves difficult for the neuroradiologist to reconcile the captured two dimensional projection data sets with the complex, three dimensional shape of the actual vascular tree.
Three dimensional images of a hollow space or hollow organ can nowadays be generated by various imaging modalities, such as magnetic resonance, computed tomography and 3D C-arm methods. Angiographic procedures are a suitable way of displaying blood vessels. In the case of 3D angiography, performed for example by means of a C-arm, a spatial display of the vascular tree is reconstructed and visualized from a plurality of preoperative or intraoperative two dimensional X-ray projection images captured from different angles. The recording techniques mentioned above provide the neuroradiologist with a spatial display of the hollow space system, for instance an intracranial vascular tree.
The gastrointestinal tract, trachea system, lymphatic system, bladder, ureter, blood vessel system etc. can be thought of as further examples of hollow spaces in the bodies of humans and animals that also include a hollow organ. There may also be other types of objects of investigation containing a hollow space or system of hollow spaces. The example of the surgical instrument designed as a catheter also needs to be taken into account.
Patent application DE 199 19 907 A1 discloses a method and a device for catheter navigation in three dimensional vascular tree recording, wherein the catheter position is determined by means of a miniaturized position detection system built into its tip and displayed in the 3-D view of the vascular tree recorded preoperatively and reconstructed in a navigation computer. The disadvantage of this method is that it does not provide the medical staff with a rapid means of guidance within the vascular tree recording.